Edge fingers are electrically conductive fingers formed on one or both sides of an edge portion of a multi-layer printed circuit board. The printed circuit board is insertable into a socketed connector provided on an electronic device such as a computer. The socketed connector is usually provided with resiliently deflectable metal contact strips which are positioned and configured to engage the edge fingers of the printed circuit board to thereby electrically couple the circuitry of the printed circuit board and the electronic device. Ideally, socketed connector should have impedance characteristics that are identical, or very close, to those of the printed circuit board (PCB) transmission lines and components connected. However, for known prior art, impedance mismatch would occur between PCB transmission lines, gold finger region in particular, and the socketed connector. Then, signal quality could be degraded. Therefore, there is a need to provide an improved edge finger structure of a multi-layer printed circuit board.
The above description of the background is provided to aid in understanding the edge fingers of a multi-layer printed circuit board, but is not admitted to describe pertinent prior art of the edge fingers of a multi-layer printed circuit board. The above description also does not constitute pertinent prior art to the edge fingers of a multi-layer printed circuit board, or does not consider any cited documents as material to the patentability of the claims of the present application.